German Patent Publication DE 3,219,457 C2 discloses a selvage cutter for a loom for severing the catch selvage from the fabric prior to rolling the fabric up on a fabric take-up roller or fabric beam. The known selvage cutter includes a positively driven scissors cutter guided along a cutting path between the fabric edge or selvage and the catch selvage. The scissors cutter is arranged in a plane extending vertically above the plane of the fabric. In order to assure a reliable guiding of the scissors cutter along a cutting path and to prevent an excursion into the fabric, one end of the known scissors cutter is suspended by a pendulum bearing that permits a limited lateral excursion in the direction of the weft insertion. The other end of the scissors cutter that dips into the cutting path or gap is equipped with guide surfaces that extend in parallel to the cutting edges for an automatic guiding of the scissors cutter in the cutting path or gap. These guide surfaces contact on the one side the fabric selvage, and on the other side the catch selvage. Even though the known scissors cutter is suspended by a pendulum roller bearing, it is not possible to track the known scissors cutter along the fabric selvage or edge in a follower manner. As a result, when for example, due to localized contractions or shrinkage of the fabric along the fabric selvage or edge, the cut weft thread ends are of uneven length because the scissors cutter cannot directly follow the fabric edge or selvage.
German Patent Publication DE 2,042,207 B2 discloses a selvage cutter for fabric edges with a fixed shearing head that is mounted in a fixed position relative to the longitudinal fabric movement toward the fabric take-up. In order to permit the shearing head to rapidly respond to varying or changing margin or edge conditions of the fabric web, the shearing head is positively driven by a cross-position adjustment drive. The drive in turn is controlled by a sensor device that produces an adjustment signal in response to a characteristic of the fabric edge, such as a shrinkage location, whereby the longitudinally stationary head is nevertheless adjustable back and forth in the weft insertion direction. Such an arrangement is quite costly.
German Patent Publication DE PS 870,230 discloses a cutter for a loom, wherein the cutter is mounted on a carrier permitting a displacement of the cutter in the direction of the weft thread insertion. A guide member made of sheet metal which is so positioned that the leno thread pairs (19) and (20) on the one hand and (21) and (22) on the other hand are constantly correcting the position of the sheet metal guide member (35). There is no disclosure how and by what elements it is assured that the sheet metal guide member will always be positively guided along the fabric edge.
French Patent Publication FR PS 2,271,320 discloses a cutter with cutting blades supported on a carrier equipped with guide elements. On the one hand these guide elements contact the fabric edge and on the other hand the guide elements contact the catch selvage downstream of the point of cutting. Such an arrangement also does not assure that the cut edge positively follows the contour of the fabric edge. This is so because the guide element that contacts the fabric edge does so voluntarily, so to speak, and is not positively biased into contact with the fabric edge.
French Patent Publication FR PS 2,426,106 discloses a cutter for a loom, wherein no guide elements are provided in the area of the cutting blades, so that a fabric edge follower motion is not possible.
German Patent Publication DE 2,435,397 A1 shows a cutter device with a tilting body to which a cutting blade carrier is attached. A movable cutting blade is connected to a blade drive for moving the cutting blade about the rotational axis of a blade journal forming part of the cutting device. A fixed cutting blade is also supported by the blade carrier which in turn is journalled on a fixed journal axis that is secured to the loom frame at a spacing from the blade journal so that the cutting device can be tilted about the fixed journal axis in a plane of the fabric which itself is supported by a fabric spreader.
Prior to the begin of any cutting for severing the catch selvage from the fabric edge, it is necessary to align and guide the cutting device relative to a cutting path or gap positioned between the fabric edge and the catch selvage which runs in parallel to the fabric edge being woven. The alignment and guiding takes place with the aid of a track follower wheel (13) secured to the cutting device. The track follower wheel runs ahead of the cutting point for determining the cutting line between the fabric edge and the catch selvage. The cutting device is tiltable about a cutter journal defining a rotational center which is positioned in the cutting plane, but spaced from the central axis of the cutter journal. The track follower wheel makes sure that the cutting device is guided substantially in parallel to the fabric edge. However, the length of the weft threads projecting out of the fabric edge after cutting may have different lengths, for example due to a localized fabric shrinkage or contraction near the fabric edge.
In connection with fabrics which have a relatively large shrinkage characteristic due to the type of material being woven, it is not possible to guide the known cutting device in follower fashion along the direction of the fabric edge. As a result, where there is a localized shrinkage at the fabric edge relatively long weft thread ends project from the fabric edge after the cutting. Additionally, these projecting relatively long weft thread ends may have individually different projecting lengths. Furthermore, in fabrics in which fabric sections with a high weft density alternate with fabric sections having a low weft density, the localized shrinkage characteristic of the fabric edge changes accordingly with these sections of different density so that again the same fabric edge has projecting weft thread ends of varying length. Such projecting weft threads of varying length are undesirable because they cause a problem in any following production processes for ready-made wearing apparel. This problem occurs when the fabric edge of a garment must be formed as a tucked-in seam which has a poor sewability due to the projecting weft ends of different lengths.
The above mentioned German Patent Publication DE 2,435,397 A1 also discloses an embodiment in which the cutting device is positioned or mounted in a plane in which the fabric is supported by a fabric spreader. Such a position limits the tiltability of the cutting device and additionally requires a spring loading. The spring loading is supposed to assure that the track follower wheel which reaches into the weft threads has a certain guide play in the direction of the fabric edge as well as in the direction of the catch selvage. Even in this version of the known cutting device, there is no assurance that the cutter will be positively guided with reference to the fabric edge in a follower fashion.